SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2439ffa3558f230da95548e5ca7562b8f90fd78bf808c8690ce55e67e6e6dc28' 
  AND token = 'RI0AsgDvhnasFc1tpQYgRQ4MdbSLoVouJS2lXEWuXkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}